1,318 research outputs found
Mapping the spatial variation of soil moisture at the large scale using GPR for pavement applications
The characterization of shallow soil moisture spatial variability at the large scale is a crucial issue in many research studies and fields of application ranging from agriculture and geology to civil and environmental engineering. In this framework, this work contributes to the research in the area of pavement engineering for preventing damages and planning effective management. High spatial variations of subsurface water content can lead to unexpected damage of the load-bearing layers; accordingly, both safety and operability of roads become lower, thereby affecting an increase in expected accidents.
A pulsed ground-penetrating radar system with ground-coupled antennas, i.e., 600-MHz and 1600-MHz center frequencies of investigation, was used to collect data in a 16 m × 16 m study site in the Po Valley area in northern Italy. Two ground-penetrating radar techniques were employed to non-destructively retrieve the subsurface moisture spatial profile. The first technique is based on the evalu¬ation of the dielectric permittivity from the attenuation of signal amplitudes. Therefore, dielectrics were converted into moisture values using soil-specific coefficients from Topp’s relationship. Ground-penetrating-radar-derived values of soil moisture were then compared with measurements from eight capacitance probes. The second technique is based on the Rayleigh scattering of the signal from the Fresnel theory, wherein the shifts of the peaks of frequency spectra are assumed comprehensive indi¬cators for characterizing the spatial variability of moisture. Both ground-penetrating radar methods have shown great promise for mapping the spatial variability of soil moisture at the large scale
Comparison of fatty acid profile in lamb meat and baby food based on lamb meat
The aim of this study was to compare the fatty acid (FA) profile of fresh lamb meat with those of baby foods based on lamb meat. For this purpose, samples of commercial homogenized (HO) and lyophilized (LIO) baby food based on lamb meat and fresh lamb meat (FM) were analyzed
for their FA composition. All fatty acids, except for oleic acid and conjugated linoleic acid (CLA), differed
among the three baby products tested. The sum of omega-6 FA and the ratio omega 6/omega 3
FA were lower in FM and LIO meat compared to HO samples. The content of total PUFA n-3 was the
highest in FM, because of its highest content of C18:3 n3, EPA, DPA and DHA compared to LIO and
HO baby food. The content of arachidonic acid was more than 6-fold higher in FM compared to LIO and
HO. This study evidenced the possibility of enhancing the FA profile of commercial baby food based on
lamb meat by using meat with healthier FA profile
ONE-POT ENZIMATIC DEPOLYMERIZATION OF CELLULOSE IN IONIC LIQUIDS
Green alternatives to fossil-based fuels are very attractive and can be produced from cellulosic materials. Cellulose is the primary product of photosynthesis in plants and has immense importance as a renewable raw material. The production of biofuels starting from cellulose is gaining increasing attention and obviously implies the partial or total hydrolysis of cellulose: enzymatic processes are considered the most promising technology [1]. Cellulases (EC 3.2.1.4) are the enzymes most commonly employed to selectively depolymerize cellulose in buffered aqueous solvents. Because of the very low solubility of cellulose due to its highly organized structure, enzymatic conversions proceed at very slow reaction rates and require the dissolution in a solvent to facilitate the access of cellulases to cellulosic substrates. To improve the yield of fermentable monosaccharides, pretreatments of cellulose, such as thermal, chemical or physical treatment, have been applied to afford a better enzymatic conversion [2].
Ionic liquids (ILs) have been increasingly recognized as excellent solvents for dissolution and pretreatment of cellulose but it was previously reported that ILs induce usually fast enzyme deactivation by protein unfolding [3].
In the present work we present a study on a single-batch, homogeneous phase enzymatic hydrolysis of cellulose using three commercial ILs. We have tested two native proteins from Trichoderma reesei and Humicola insolens and two engineered proteins from T. reesei and Streptomyces sp.. In some cases ILs don’t denature the cellulases used but increase their operational stability as compared to standard buffer solutions and facilitate the dissolution of cellulose. Interestingly, the stability of the four cellulases in the presence of the ILs allows to set-up a procedure lacking of the cellulose pretreatment step.
We believe that this strategy could be amenable of scale-up and innovative industrial applications for the efficient one-batch conversion of inexpensive cellulosic materials into derivatives (biofuels, derivatized cellulose, monosaccharides for fine chemicals, etc.) with high potential commercial interest and in the framework of environmentally friendly chemistry.
References
[1] A.P. dadi, S. Varanasi, C.A. Schall. Biotechnol Bioeng, 95(5), 904-910, (2006).
[2] M.B. Turner, S.K. Spear, J.G. Huddleston, J.D. Holbrey, R.D. Rogers. Green Chem, 5(4), 443-447, (2003).
[3] S.D. Zhu, Y.X. Wu, Q.M. Chen, C. Wang, S. Jin, Y. Ding, G. Wu, Green Chem, 8, 325-327, (2006)
A Combined Experimental and Theoretical Study on the Stereodynamics of Monoaza[5]helicenes: Solvent-Induced Increase of the Enantiomerization Barrier in 1-Aza-[5]helicene
Helicenes and heterohelicenes are attractive compounds with great potential in materials sciences to be used in optoelectronics as ligand backbones in enantioselective catalysis and as chiral sensors.[1] Synthetic protocols were developed to obtain helicenes with skeletons consisting of ortho-fused benzene rings or analogue structures incorporating a heteroatom, as in thiophene-, furane-, or pyridine-containing helicenes.[2] In recent years, a repertoire of synthetic strategies was developed to access all monoaza[5]helicenes as well as some diaza[ 5]helicenes.[3] The properties of these materials are related to the stereodynamics of these helical chiral compounds. By exploration of the unexpected broad range of physicochemical properties of aza[n]helicenes it was realized that there is an opportunity to modulate a specific property by controlled design of the position of the N atoms in the helical molecular frame. In this contribution, we show a complete stereodynamic characterization of monoaza[5]-helicenes combining enantioselective dynamic HPLC and DFT calculations. At variance with previous theoretical calculations[4], 1-aza[5]helicene shows a surprisingly high enantiomerization barrier, which is triggered by specific solvent interactions. [5]
References
[1] a) H. A. Staab, M. A. Zirnstein, C. Krieger, Angew. Chem. Int. Ed. Engl. 1989, 28, 86–88; Angew. Chem. 1989, 101, 73– 75;b) T. R. Kelly, Acc. Chem. Res. 2001, 34, 514 –522; c) T. J. Wigglesworth, D. Sud, T. B. Norsten, V. S. Lekhi, N. R. Branda, J. Am. Chem. Soc. 2005, 127, 7272 – 7273; d) L. Vyklicky´, S. H. Eichhorn, T. J. Katz, Chem. Mater. 2003, 15, 3594 –3601; e) M. Gingras, Chem. Soc. Rev. 2013, 42, 1051– 1095.
[2] a) M. Gingras, Chem. Soc. Rev. 2013, 42, 968–1006; b) M. Gingras, G. F_lix, R. Peresutti, Chem. Soc. Rev. 2013, 42, 1007 –1050; c) Y. Shen, C.-F. Chen, Chem. Rev. 2012, 112, 1463– 1535.
[3] a) C. Bazzini, S. Brovelli, T. Caronna, C. Gambarotti, M. Giannone, P. Macchi, F. Meinardi, A. Mele, W. Panzeri, F. Recupero, A. Sironi, Eur. J. Org. Chem. 2005, 1247 – 1257; b) S. Abbate, C. Bazzini, T. Caronna, F. Fontana, C. Gambarotti, F. Gangemi, G. Longhi, A. Mele, I. Natali Sora, W. Panzeri, Tetrahedron 2006, 62,139 –148; c) T. Caronna, F. Fontana, A. Mele, I. Natali Sora, W. Panzeri, L. Vigan_, Synthesis 2008, 413– 416; d) T. Caronna, S. Gabbiadini, A. Mele, F. Recupero, Helv. Chim. Acta 2002, 85, 1 –8; e) T. Caronna, F. Castiglione, F. Fontana, D. Mendola, I. Natali Sora, Molecules 2012, 17, 463 –479.
[4] S. Abbate, C. Bazzini, T. Caronna, F. Fontana, F. Gangemi, F. Lebon, G. Longhi, A. Mele, I. Natali Sora, Inorg. Chim. Acta 2007, 360, 908 –912.
[5] T. Caronna, A. Mele, A. Famulari, D. Mendola, F. Fontana, M. Juza, M. Kamuf, K. Zawatzky, and O. Trapp, Chem. Eur. J. 2015, 21, 1–7
Clinical, epidemiological and virological features of acute hepatitis B in Italy
Purpose To evaluate the association of hepatitis B virus
(HBV) genotypes, basal core promoter (BCP)/precore (PC)
and S gene mutations with the clinical-epidemiological
characteristics of acute hepatitis B (AHB) in Italy.
Methods During July 2005–January 2007, 103 symptomatic AHB patients were enrolled and prospectively followed up at 15 national hospitals. HBV genotypes, BCP/
PC and S gene variants were determined by nested-PCR
and direct sequence analysis.
Results Genotype D, A and F were detected in 49, 45
and 6 % of patients, respectively. BCP, PC, and BCP
plus PC variants were found in 3.1, 11.3 and 7.2 % of
patients, respectively. At enrollment, 68.3 % of patients
were hepatitis B e antigen (HBeAg)-positive and 31.7 %
HBeAg-negative. BCP/PC mutations were more common in HBeAg-negative than in HBeAg-positive patients
(p < 0.0001). Compared to genotype D patients, those harboring non-D genotypes were more frequently males
(p = 0.023), HBeAg-positive (p < 0.001), had higher
bilirubin (p = 0.014) and viremia (p = 0.034) levels and
less frequently carried BCP/PC mutations (p < 0.001).
Non-D genotype patients more often were from Central Italy (p = 0.001) and reported risky sexual exposure
(p = 0.021). Two patients had received vaccination before
AHB: one harbored genotype F; the other showed a S gene
mutation. Four patients developed fulminant AHB; mutations were found in 2 of 3 patients who underwent BCP/
PC sequencing. After a 6-month follow-up, only 2 (2.8 %)
patients developed persistent infection.
Conclusion AHB by non-D genotypes is increasing in
Italy and is associated with risky sexual exposure. The ability of some genotypes to cause persistent and/or severe
infection in Italy warrants larger studies for clarificatio
Association and diffusion of Li+ in carboxymethylcellulose solutions with application to environmentally friendly Li-ion batteries: a combined Molecular Dynamics and NMR study
Carboxymethylcellulose (CMC) has been proposed as a polymeric binder for the electrodes in environmentally friendly Li-ion batteries. Its physical properties and interaction with Li+ ions in water are interesting from the point of view of electrode preparationprocessability in water is one of the main reasons for its environmental friendlinessbut also for its possible application in aqueous Li-ion batteries. We combine MD simulations and variable-time PFGSE-NMR spectroscopy to investigate Li+ transport in CMC-based solutions. Both simulation and experiment show that, at concentrations such that Li-CMC has a gel like consistency, the Li+ diffusion coefficient is still very close to that in water. These ions interact preferentially with CMC’s carboxylate groups, giving rise to a rich variety of coordination patterns. However, the diffusion of Li+ in these systems is essentially unrestricted, with a fast, nanosecond-scale exchange of the ions between CMC and the aqueous environment
Multiple points of view of heteronuclear NOE: long range vs short range contacts in pyrrolidinium based ionic liquids in the presence of Li salts.
The nuclear Overhauser enhancement (NOE) is a powerful tool of NMR Spectroscopy extensively used to gain structural information in ionic liquids (ILs). A general model for the distance dependence of intermolecular NOE in ILs was recently proposed showing that NOE spots beyond the first solvation shell and accounts for long-range effects. This conclusion prompted for a deep rethinking of the NOE data interpretation in ILs. In this paper we present an extensive and quantitative study of N-propyl-N-methyl pyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR13TFSI), the homologue with bis(fluorosulfonyl)imide (PYR13FSI), and their mixtures with LiTFSI based on {1H-19F} and {1H-7Li}NOE correlation experiments (HOESY). The former is mainly tuned on long-range interactions, the latter on short-range ones, due to the small and large Larmor frequency differences of the involved nuclei. The collected data are discussed in two different way: long-range {1H-19F}NOEs spot on the polar/apolar domains within the ILs, whereas short-range (e.g. regarding the first coordination shell) {1H-7Li}NOEs describe the contacts between first neighbors, with interesting correlation with the distances’ statistics derived by crystallographic data of related systems
Preoperative staging of colorectal cancer using virtual colonoscopy: correlation with surgical results
The aim of this study was to evaluate the clinical usefulness of computed tomography colonography (CTC) in the preoperative staging in patients with abdominal pain for occlusive colorectal cancer (CRC) and to compare the results of CTC with the surgical ones
Effect of Quebracho tannin extract on soybean and linseed oil biohydrogenation by solid associated bacteria: an in vitro study
An in vitro trial was carried out to study the effects of Quebracho tannins extract (QE) on fatty acid profile of rumen solid adherent bac- teria (SAB) during the fermentation of diets supplemented with soybean or linseed oil, as sources of linoleic (LA; 18:2 n-6) and α- linolenic acid (α-LNA; 18:3 n-3), respectively. Two control diets were prepared using a basal mixture of grass hay [760 g/kg on dry matter (DM)], soybean meal (55 g/kg DM), barley meal (130 g/kg DM), vitamin mineral premix (20 g/kg DM) and 35 g/kg DM of soybean (SOC diet) or linseed oil (LOC diet) as lipid supple- ment. Other two diets (SOCT and LOCT) were obtained by integrating SOC and LOC with QE (49 g/kg DM). The results confirmed that Quebracho tannins may be an effective method for reducing in SAB the biohydrogena- tion of LA (17.3 vs 34.5 g/100 g of fatty acid in SOC and SOCT, respectively) and LNA (10.7 vs 21.4 g/100 g of fatty acid in LOC and LOCT, respectively), but not for increasing the rumen accumulation of cis9, trans11 18:2 (0.77 vs 0.32 g/100 g of fatty acid in SOC and SOCT, respec- tively; 0.51 vs 0.43 g/100 g of fatty acid in LOC and LOCT, respectively) and trans11 18:1 (6.15 vs 3.64 g/100 g of fatty acid in SOC and SOCT, respectively; 5.53 vs 4.47 g/100 g of fatty acid in LOC and LOCT, respectively)
Compatibility of Imidazolium-Based Ionic Liquids for CO2 Capture with Steel Alloys: A Corrosion Perspective
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